Conventionally, wheels such as automotive passenger vehicle road wheels have been made of steel to provide adequate strength and durability. Such wheels must support a proportional share of the weight of the vehicle and must reliably and safely transmit the driving and braking torques between the tire and the axle hub. Such conventional steel wheels are disadvantaged, however, by their weight. In view of the growing interest in improved fuel economy, it is desirable to reduce as much as possible the weight of all vehicle components, including the wheels.
Other metals, such as, for example, aluminum have been used in place of steel to make vehicle wheels. In view of the greater cost of aluminum as compared to steel, however, aluminum wheels are typically fashioned as so-called styled aluminum wheels which are decorative and can be marketed at prices sufficient to recover the increased cost. It would be desirable, therefore, to produce styled wheels at a cost lower than that possible for aluminum styled wheels.
In the past, there have been efforts to fabricate a vehicle wheel of synthetic material. In U.S. Pat. No. 3,369,843 to Prew it was suggested that a wheel structure could be formed by building up a plurality of laminations of fiber reinforced synthetic resin materials. This method employed a cup-shaped circular mold for each half of the final wheel structure. Triangular shaped plies of reinforced resin referred to as "glass fabric cloth" were laid into the mold in overlapping relation around a central locating pin. In U.S. Pat. No. 3,917,352 to Gageby a filament winding technique is suggested for fabricating a vehicle wheel. In U.S. Pat. No. 3,811,737 to Lejeune a one-piece wheel of reinforced resin material is suggested, characterized in that the periphery of each of a plurality of hub-fastening holes is reinforced by rigid plate means such as small plates of rigid material embedded in the thickness of the disc or so-called "spider" portion of the wheel. In U.S. Pat. No. 4,072,358 to Ridha a compression molded cut-fiber reinforced plastic wheel is suggested, wherein the rim, disc and hub portions of the wheel are all uniformly and predominantly axially reinforced by cut glass fibers located in planes parallel to the axis of the wheel.
It is an object of the present invention to provide a one-piece compression molded vehicle wheel having strength and durability equal to or better than that required of steel vehicle wheels. It is also an object of the invention to provide such one-piece fiber reinforced synthetic material wheels as styled wheels at a cost far less than that of aluminum styled wheels.
It is another object of the invention to provide a fiber reinforced synthetic material vehicle road wheel which can be produced in one piece by compression molding. These and other objects of the invention will be more apparent from the following description of the invention.